The role of lactose in in ‘lac operon’ are-:
1. A low level of beta-galactoside permease enzyme persists in the cell even when the Lac operon is inactive, allowing minimal lactose entry.
2. Lactose binding to the repressor renders it inactive.
3. The repressor-lactose complex loses its ability to bind to the operator gene, leading to the activation of the operon.
4. RNA polymerase transcribes structural genes, resulting in the production of lac mRNA and subsequent enzyme synthesis.
5. Lactose functions as an inducer, initiating the operon’s transcriptional activity.
6. Declining inducer levels prompt the repressor to block the operator again, repressing structural gene expression—a negative feedback mechanism.